Development of sourdough fermentation protocols for an extended mold-free storage life of packaged pan bread

面包的微生物变质是由绳索状芽胞杆菌引起的，这种芽胞杆菌作为种子内生菌沉积在谷物中，总是出现在小麦和黑麦面粉中，而菌丝真菌（霉菌）则在烘焙后污染面包。即使使用少量的酵母或以酵母为基础的面包改良剂也能可靠地抑制杆菌的腐败，但在超过3周的储存时间内，使用酵母通常不足以完全抑制霉菌的生长。乳酸菌具有抗真菌活性的代谢物包括乙酸、丙酸、长链羟基脂肪酸、苯乳酸和环二肽。这些抗真菌代谢物要么以不足以抑制霉菌生长的浓度产生（长链羟基脂肪酸、苯乳酸和环二肽），要么以抗真菌浓度存在（乙酸、丙酸、环二肽）时对面包质量产生负面影响。因此，延长面包无霉菌储存寿命的成功方法是将乳酸菌的抗真菌代谢物（尤其是乙酸）与抗真菌添加剂（如山梨酸或丙酸）或含有抗真菌成分的成分（如啤酒花提取物、富含酚酸的植物提取物或可通过脂解释放抗真菌脂肪酸的植物籽油）结合起来。这个为期3年的项目项目的总体目标是开发一种酵母发酵工艺，有助于面包的无霉菌保质期，并确定具有抗真菌活性的成分，以补充酵母的抗真菌活性，并达到符合行业标准的无霉菌储存寿命。

Microbial spoilage of bread is caused by rope-forming bacilli, which invariably occur in wheat and rye flour as they are deposited in cereal grains as seed endophytes, and by mycelial fungi (molds), which contaminate bread after baking. The use of even low amounts of sourdough or sourdough-based bread improvers reliably inhibits spoilage by bacilli but the use of sourdough is typically insufficient to completely inhibit mold growth during a storage time of more than 3 weeks. Metabolites of lactobacilli with antifungal activity include acetic acid, propionic acid, long-chain hydroxy fatty acids, phenyllactic acid, and cyclic dipeptides. These antifungal metabolites are either not produced in concentrations that are sufficient to inhibit mold growth (long-chain hydroxy fatty acids, phenyllactic acids and cyclic dipeptides), or negatively impact bread quality when present in antifungal concentrations (acetic acid, propionic acid, cyclic dipeptides). Successful approaches to extend the mould-free storage life of bread therefore combined antifungal metabolites of lactobacilli, particularly acetic acid, with antifungal additives, e.g. sorbic or propionic acids, or ingredients with antifungal components, e.g. hop extracts, plant extracts rich in phenolic acids, or plant seed oil from which antifungal fatty acids can be released by lipolysis. This 3 year project project generally aims to develop a sourdough fermentation process that contributes to the mold free shelf life of bread, and to identify ingredients with antifungal activity that complement the antifungal activity of sourdough and achieves a mold-free storage life that matches industry standards.